Rain or sleet is forecast once the snowfall eases on Sunday morning, but then clear skies will lead to widespread icy patches forming across much of England and Wales, the Met Office said, advising people to “be prepared”.

At Luton Airport 10cm of snow fell overnight and its runway was closed for a period, causing three departing flights to be cancelled. But so far there have been no cancellations for Sunday, although the majority of flights are delayed for an hour or more.

Temperatures have been so low that waterfalls in Yorkshire have frozen

British Airways said it would allow passengers scheduled to fly on Sunday to re-book for journeys between Monday and Thursday.

Stansted airport in Essex closed on Saturday night for a period to clear snow from its runway, while Birmingham Airport reopened after snow was cleared from the runway.

Leeds Bradford Airport has warned of delays or cancellations.

Richard Scott, from BAA, said because Heathrow operated at capacity, there was no slack in the system to deal with the reduced number of flights that could take off and land in bad weather.

He added: “If you can imagine you’re driving, you have to drive slower, leave more space for the car in front in fog, strong winds, snow. It’s the same with aircraft.

“If we don’t proactively cancel flights, the delays build and build and build and it’s much worse for passengers.”

“There are circumstances in which it is better for the airlines to act proactively rather than, as we have seen in the past, apparently being caught unawares and then the level of delays being experienced by passengers goes up, not down.”

On the roads, Thames Valley Police said as many as 100 vehicles were stationary on the M40 between Junction 4 High Wycombe and Junction 9 Bicester for several hours and snow ploughs were brought in to help clear the roads.

Motorist Katie Jones told BBC News she had spent hours sitting in her car on the M25 in Hertfordshire.

“We were stationary for about seven and a half hours. We passed cars abandoned in the side of the road, having crashed off. We passed lorries jack knifed across two, three lanes of the motorway and it’s been impassable in large part.”

This included the Central Line, where passengers became stuck on a train that broke down between Snaresbrook and South Woodford and say they were asked to walk 15 minutes down the tracks to the next station.

The RAC’s Kevin Andrews said heavy snow and sub-zero temperatures would create “a dangerous cocktail of driving conditions” and urged drivers to stay at home where possible.

February has seen daytime temperatures plunge four or five degrees lower than average over the past few days, and cold conditions are likely to continue into the early part of next week.